Steam-generating boilers are generally large structures containing numerous boiler tubes, usually made of steel, that are in thermal contact with a burning fuel, such as coal. The burning fuel heats water circulating through the boiler tubes. The heated water, or more usually the resulting steam, is used to drive turbines for generation of electricity or other purposes. In order to facilitate thermal transfer to the water in a boiler tube, heat transfer fins are placed around the boiler tube. They are typically brazed or welded to the boiler tube by high frequency welding. Because of deterioration due to corrosion and the like, boiler tubes may require replacement. Ordinarily repair of a damaged boiler tube involves cutting and removal of the damaged section of the tube and replacement with a new section. The section of boiler tube to be replaced is generally cut out using a power saw or cutting torch. However, heat transfer fins on the boiler tube must first be removed to gain access to the boiler tube. Removal of the heat transfer fins from the boiler tube has, before the present invention, been done with portable power tools such as a grinding tool having a rotary abrasive wheel or with air chisels. These techniques are at best time consuming.
In addition, after removal of the damaged section of boiler tube, it may be necessary to remove heat transfer fins at or near the end of the remaining tube ends and to prepare the tube ends for welding to a new section of boiler tube. Proper preparation of the exposed tube ends requires beveling of the exposed tube ends for a good weld. More specifically, the exposed tube ends should have a frustoconical bevel to facilitate a good weld. It is highly desirable that this be done as quickly as possible.
It is, therefor, an object of the present invention to remove heat transfer fins from boiler tubes, more quickly and efficiently, and at the same time to bevel the exposed tube ends.